实验性单纯疱疹病毒性角膜炎角膜神经损伤的观察

Observation of the morphological changes of corneal nerve in experimental herpes simplex keratitis in rabbit eyes

目的观察兔实验性单纯疱疹病毒性角膜炎(HSK),不同病程阶段的角膜神经组织损伤的显微及超微结构的改变。方法兔角膜刮痕接种HSVⅠ,多聚酶链反应技术检测兔角膜感染,分期进行角膜美蓝活组织染色,光镜及透射电镜下观察角膜神经的改变。结果感染HSK后第4天光镜下即出现角膜神经纤维稀疏、变细,中央神经网密度下降。至7～14d,神经损伤显著。第30天,仍未达到正常的神经网密度。电镜下,HSK后第4天,上皮内神经末梢轴膜不完整,轴浆部分溶解。第7～14d,神经损伤严重。第30天,神经轴膜仍不完整,轴浆内微管及小泡减少。结论HSK导致角膜神经纤维损伤及神经网密度下降,且角膜神经损伤恢复较慢。

Objective To observe the morphological changes of corneal nerve in experimental herpes simplex keratitis (HSK) in rabbit eyes. Methods Inoculation of the scarified cornea with herpes simplex virus-Ⅰ(HSV-Ⅰ)leads to herpetic infection of cornea. The HSK was detected by slit lamp and polymerase chain reaction(PCR), and the changes of corneal nerves in various periods with methylene blue vital staining and ultrastructure of corneal nerve were studied. Results Under light microscope, fewer corneal nerve bundles were observed, scattered with lower density of nerve fiber at center of cornea on the 4th day after the infection. At days 7 and 14, the seriously damaged nerve fiber was intermittent. The neuraxon became shorter with little polarity and the density of nerve fiber was extremely low. At day 30, the density was still low while the nerve fiber was approximately normal. Under electromicroscope, at day 4, the lamellar sheath of nerve fiber in the epitheliums appeared intermittent, and the neuroplasm of endings was partly lysed. During day 7 to day 14,neuroplasm was damaged and became vacuolar. The mitochondria swelled with vacuolar crest, and then were destroyed and lysed. The nerves in stroma were also injured. On day 30, neurilemma sheath was still intermittent with the decrease of microfilament and racuole. Conclusion HSK leads to the damage of nerve and the decrease of nerval density, and the damage of corneal nerve repairs very slowly.